Objective: The middle cerebral artery (MCA) is the most commonly treated artery in mechanical thrombectomy stroke trials; however, there is no pragmatic agreement about the segmental anatomy and nomenclature utilized. It results in significant clinical-radiological dissociation and introduces bias in research trials. The purpose of the study is to review and compare angiographic anatomy with microsurgical anatomy literature of the MCA with emphasis on the discrepancy. Methodology: Consecutive cerebral angiograms between January 2011 and March 2014 were retrospectively reviewed by endovascular surgical neuroradiologists. Information about the anatomy of the sphenoidal segment of the MCA classified as classic and non-classic pattern, the lenticulostriate artery takeoff pattern, and the course angulation of the sphenoidal segment were studied. Results: A total of 500 patients, 886 cerebral angiograms, were reviewed. We found the classic pattern of the main trunk MCA bifurcation and a straight angulation course in less than half of the cases. The lenticulostriate arteries arose not only from the main trunk but also from its divisions in more than half of the cases. Conclusion: It is important to corroborate our findings and to develop a pragmatic classification to accurately assess MCA occlusions from the radiological and clinical perspective.

Background: Stent-assisted coiling (SAC) leads to significant changes in the vascular angle altering the bifurcation geometry and the hemodynamics at the bifurcation apex. It is believed that the stent alone exerts this effect, but other possible factors have not been studied. Purpose: To study the factors contributing to angular remodeling following SAC of bifurcation aneurysms including the anatomical, stent-related, and coil-related factors. Materials and Methods: We reviewed 43 basilar and carotid bifurcation aneurysms treated by SAC using Neuroform EZ (n = 28), Enterprise (n = 8), and Lvis Jr. (n = 7) stents. The bifurcation angle between the mother and stented daughter vessel was measured in 4 settings: pretreatment, poststenting, postcoiling, and at delayed follow-up (6–12 months). The degree of stent-induced angular remodeling was calculated by subtracting the poststenting bifurcation angle from the pretreatment one, while the coil-induced angular remodeling was calculated as the difference between the postcoiling and poststenting bifurcation angle. The immediate postprocedural degree of angular remodeling is the sum of the stent- and coil-induced angular remodeling. We studied the effect of several factors including the pretreatment bifurcation angle, aneurysm site, diameter of parent vessel, stent type, stent length in the daughter vessel, postoperative actual in situ coil size, and packing density. Results: The mean degree of stent-induced and coil-induced angular remodeling was 10.2 (0–47) and 4.53 (–7 to 30), respectively. The immediate postprocedural and delayed angular remodeling was 14.8 (–4 to 47) and 4.75 (–12 to 40), respectively. The degree of immediate remodeling was significantly affected by the actual in situ coil size (p = 0.017), and the pretreatment bifurcation angle (p = 0.024). Linear regression was carried out and the pretreatment bifurcation angle was defined as a predictor. The degree of delayed remodeling is significantly affected only by the pretreatment bifurcation angle (p = 0.011). Conclusion: Immediate angular remodeling following SAC of bifurcation aneurysms can happen after stenting or coiling or both. This is the first study reporting the role of the coils as an additional factor beside the stent in inducing immediate angular changes; this effect is correlated to the size of the coils. The pretreatment bifurcation angle is the most consistent factor affecting the degree of both immediate and delayed angular remodeling.

The road to Comprehensive Stroke Center (CSC) certification is challenging and requires full integration of neurological, neurosurgical, neurointerventional, and neurocritical care and rehabilitation services across the entire continuum of care. To successfully achieve this level of certification, centers must coordinate significant resources and services into an organized program. This paper is the first in a three-part series outlining common pitfalls facing many organizations during their journey to initial CSC certification and re-certification and offers a roadmap and pearls for success on this journey. Setting the vision for certification is a key first step in the certification process. This includes fully understanding the certification standards, requirements, and supporting documents. Program leadership must then conduct a thorough gap analysis and build a business plan to support the program as it transitions to a CSC. These key steps should inform the timeline for certification application.

Objective: To determine the safety and efficacy of flow reversal following proximal flow arrest as an embolic protection strategy for carotid angioplasty and stenting (CAS) with short-term follow-up. Method: We performed a retrospective review of our CAS database for patients who underwent stent-supported carotid revascularization in the setting of acute/subacute stroke or TIA. We reviewed clinical and radiographic data during a 36-month period. Primary outcome was clinical evidence of ipsilateral stroke in the first 30 days. Secondary outcomes include clinical outcomes and sonographic and/or angiographic follow-up over 6 months, 6-month functional scale, and all-cause mortality. Results: Fifty-five patients underwent CAS using flow reversal: 26 females and 29 males with a mean age of 69.7 years. Median time to treatment from index event was 3 days. 11% underwent stenting as part of hyperacute stroke therapy. Average luminal stenosis was 86%. The 9-Fr Mo.Ma device was used in combination with Penumbra aspiration in all cases. There were no ipsilateral strokes. Incidence of any ischemic event was 3.64%, but only 1 (1.82%) patient had a postoperative stroke. Clinical follow-up was available for 94.5%, while lesion follow-up was available for 73% of patients. Three patients had evidence of restenosis, but none were symptomatic. Luminal restenosis was ≤30% in all three. Median pre- and post-NIHSS were 1 and 1, respectively. Conclusion: Flow reversal using the Mo.Ma device is a safe and effective strategy in preventing distal embolization during carotid artery revascularization.

Background: Recent reports have raised various concerns about the risk of vessel wall injury while withdrawing current laser-cut stent retrievers during active strut apposition to the vessel walls. The development of braided thrombectomy assist devices in conjunction with aspiration systems may be gentler on the fragile brain vessels and more optimized with regard to the radial force (RF) for vessel diameters of proximal (M1) and distal (M2) large vessel occlusions (LVOs). Methods: Mechanical bench testing of the RF was performed using a radial compression station mounted on a tensile testing machine. The total RF in newtons (N) generated in vessels with diameters ranging from 2.25 to 3 mm as seen in proximal LVOs (∼M1), and in vessel diameters ranging from 1.5 to 2.24 mm as seen in distal LVOs (∼M2), was measured. The outer diameter of each stent was recorded, and an RF ≤1 N was grouped as “low,” while an RF >1 N was grouped as “high” for this analysis. Results: The total RFs of all laser-cut stent retrievers were all higher in the simulated M2 vessels (>1 N) than in the M1 vessels (<1 N), whereas the total RFs of the braided thrombectomy assist devices were uniformly low in both the simulated M1 and the simulated M2 vessels. Conclusions: Novel braided thrombectomy assist devices in conjunction with aspiration systems have lower RFs than existing laser-cut stent retrievers in M1 and M2 vessel diameters. Further in vivo studies are needed to delineate the impact of lowering the RF on vessel wall integrity.

Objective: To examine outcomes for thrombectomy devices used for treatment of acute ischemic stroke (AIS) with middle cerebral artery (MCA) M2 segment emergent large vessel occlusion (ELVO) as the optimal device for such reperfusion is not clearly defined. Methods: A retrospective cohort study of consecutive AIS patients with MCA M2 ELVO undergoing thrombectomy from 3 academic medical centers was conducted from October 1999 through June 2016. The patients were divided based on the device utilized. Multivariate analysis of associations between devices (stent retriever or aspiration only [manual or pump aspiration system]) was performed. Primary outcomes were good recanalization (i.e., modified thrombolysis in cerebral infarction score ≥2b) and a favorable modified Rankin scale (mRS) score (i.e. ≤2). The secondary outcome was symptomatic intracerebral hemorrhage (sICH). Results: A total of 197 AIS patients underwent MCA M2 ELVO thrombectomy with either a stent retriever (n = 120) or aspiration only (n = 77). The aspiration-only group utilized either manual (n = 38) or pump aspiration (n = 39). Utilization of a stent retriever over manual aspiration is independently associated with higher odds of a favorable mRS score (OR = 3.2; 95% CI 1.02–9.7) and lower odds of sICH (OR = 0.09; 95% CI 0.03–0.31). Utilization of a stent retriever over a pump aspiration system is independently associated with higher odds of good recanalization (OR = 3.8; 95% CI 1.5–9.6). Utilization of a newer-generation pump aspiration catheter compared to a stent retriever resulted in similar rates of favorable mRS scores, sICH, successful recanalization, and mortality. Conclusion: Utilization of a newer-generation pump aspiration catheter compared to a stent retriever resulted in similar outcomes, but worse outcomes were seen with the manual aspiration technique. These findings need to be confirmed with a large randomized trial utilizing stent retrievers and newer-generation pump aspiration systems.

Background: Successful reperfusion after endovascular thrombectomy (EVT) correlates with good outcome. However, radiographic reperfusion does not always translate into good clinical outcomes even if the reperfusion occurs early after the stroke onset. Reasons for neurological worsening (NW) are thought to be many, such as progression of the stroke, hemorrhagic conversion post tissue plasminogen activator and/or EVT, and procedural complications such as vessel dissection or perforation, distal emboli, and re-occlusion. Data on patients worsening in the acute phase after EVT are limited. Objective: We studied the factors associated with acute NW and also identified the predictors of NW after EVT and its association with poor outcome at discharge. Methods: A retrospective cohort from a single comprehensive stroke center includes patients with acute ischemic stroke and large vessel occlusion in anterior and posterior circulation who presented between December 2014 and May 2017 and received EVT were reviewed. Primary outcome was defined as acute NW defined as change in NIHSS ≥4 from baseline in the first 24 h after EVT. Secondary outcome were modified Rankin scale (mRS) 0–2 at discharge and final infarct volume. Univariate and multivariate analyses were performed to evaluate clinical and radiographic variables independently correlating with NW after EVT. Receiver operating curve analysis was also performed to identify predictors. Results: 178 patients were included in the analysis, 26 (14.7%) met the criteria for acute NW. For these 178 patients, the median age was 63 (IQR 53–74, range 26–89), baseline median NIHSS was 19 (IQR 14–24, range 5–37), ASPECTS was 8 (IQR 7–9, range 4–10), admission median systolic blood pressure (SBP) was 150 (IQR 131–170, range 94–287), and initial median blood glucose (BG) was 123 (IQR 106–157, range 69–433). The most common reasons for worsening were progression of the stroke (42.3%) and reperfusion injury PH-2 (26.9%) (p < 0.0001). Univariate logistic analysis showed that race, ASPECTS, collateral score, diabetes mellitus, admission SBP, and admission BG were associated with acute NW. In multivariate analysis, only admission BG (OR 1.00, CI 1.00–1.01, p = 0.04) was found to have a significant association with acute NW. We ran a prediction analysis for variables and found the area under the curve to be 0.75. Finally, there was strong association between NW and poor outcome at discharge (MRS 3–6, p < 0.01) by Fisher’s exact test. About 46.1% in the NW group died during hospitalization compared to 10% in the non-NW group (p < 0.0001). Conclusion: Our single-center retrospective cohort result is limited by small sample size. It showed that high admission BG is an independent predictor of NW after EVT and ultimately leads to poor outcome.

First pass success (FPS) can be defined as in vitro retrieval of clot in a single pass during mechanical thrombectomy (MT) for acute large vessel occlusion (LVO). Despite advancements in MT technology, retrieval of fibrin-rich clots remains a challenge. Therefore, the effect of stent retriever length on FPS for fibrin-rich clots was investigated by using Solitaire^TM 6 × 40 versus 6 × 30 mm devices with a balloon guide catheter (BGC) or distal access catheter (DAC) and sheath, in an in vitro model of anterior circulation neurovascular anatomy. Additionally, vascular safety of the Solitaire^TM 6 × 40 versus 6 × 30 mm devices was evaluated in a porcine model for differences in: luminal thrombus, inflammation, endothelial coverage, fibrin deposits, smooth muscle cell loss, elastic lamina and adventitia disruption, intimal hyperplasia, and lumen reduction, at 0, 30, and 90 days post-treatment. In vitro overall FPS was measured as: Solitaire^TM 6 × 40 (95%) and Solitaire^TM 6 × 30 (67%). FPS for clot location in middle cerebral artery was: (a) BGC (6 × 40 mm: 100%; 6 × 30 mm: 100%; n = 8); (b) DAC with 088 sheath (6 × 40 mm: 83%; 6 × 30 mm: 33%; n = 12). FPS for clot location in internal carotid artery was: (a) BGC (6 × 40 mm: 100%; 6 × 30 mm: 80%; n = 11); (b) DAC with 088 sheath (6 × 40 mm: 100%; 6 × 30 mm: 67%; n = 10). Stent length had a significant effect (Fisher’s exact test; p < 0.05) on FPS. In vivo evaluation in the porcine model showed no difference in vascular safety parameters between the Solitaire^TM 6 × 40 and 6 × 30 mm devices (p > 0.05) at all time points in the study. Longer stent retrievers may be safe and effective in improving FPS for fibrin-rich clots in in vitro and in vivo models of LVO.

Idiopathic intracranial hypertension (IIH) is a rare, ill-understood disease of significant morbidity. Because the pathophysiology is poorly understood, treatment protocols are not uniform and are directed towards alleviating the most common symptoms: headache and visual loss. In this review, we analyze 25 case series, all of which included IIH patients (n = 408) who were treated with placement of a venous sinus stent. Among 342 patients who had headache, 240 patients (70.2%) had improvement or resolution of headache after the stent insertion. Of the 217 patients documented to have visual problems, visual acuity was improved or stabilized in 161 patients (74.2%). Of the 304 patients with papilledema, 257 showed resolution or improved (84.5%). Of the 124 patients who presented with pulsatile tinnitus, it was resolved in 110 patients (88.7%) after stent placement. Endovascular management of dural sinus stenosis is therefore clinically efficacious in patients with IIH who have failed medical and surgical therapy.

Background: Induced hypertension has been used to promote cerebral blood flow under vasospastic conditions although there is no randomised clinical trial to support its use. We sought to mathematically model the effects of vasospasm on the cerebral blood flow and the effects of induced hypertension. Methods: The Anatomically Detailed Arterial Network (ADAN) model is employed as the anatomical substrate in which the cerebral blood flow is simulated as part of the simulation of the whole body arterial circulation. The pressure drop across the spastic vessel is modelled by inserting a specific constriction model within the corresponding vessel in the ADAN model. We altered the degree of vasospasm, the length of the vasospastic segment, the location of the vasospasm, the pressure (baseline mean arterial pressure [MAP] 90 mm Hg, hypertension MAP 120 mm Hg, hypotension), and the presence of collateral supply. Results: Larger decreases in cerebral flow were seen for diffuse spasm and more severe vasospasm. The presence of collateral supply could maintain cerebral blood flow, but only if the vasospasm did not occur distal to the collateral. Induced hypertension caused an increase in blood flow in all scenarios, but did not normalise blood flow even in the presence of moderate vasospasm (30%). Hypertension in the presence of a complete circle of Willis had a marginally greater effect on the blood flow, but did not normalise flow. Conclusion: Under vasospastic condition, cerebral blood flow varies considerably. Hypertension can raise the blood flow, but it is unable to restore cerebral blood flow to baseline.